Diseases such as diabetes mellitus, hyperlipidemia, and hypertension are considered to develop due to an external factor such as a genetic factor, stress, and a pathogen in combination with a lifestyle habit such as an inappropriate eating habit, a lack of exercise, smoking, and excessive alcohol consumption, and these diseases are called a lifestyle-related disease (Non-Patent Document 1). The number of people having or highly likely to have a lifestyle-related disease is increasing as a result of a change in lifestyles and an increase in the elderly population, and thus a comprehensive countermeasure against lifestyle-related diseases needs to be implemented. The Ministry of Health, Labour and Welfare of Japan has begun to strengthen their approach to the above issue, proposing “firstly, exercise, secondly, diet, completely quit smoking, then a medicine comes last” as a catchphrase with the aim of improving lifestyles (Non-Patent Document 2). As exercise therapy for a lifestyle-related disease, an effect of aerobic exercise becomes a focus of attention in sports facilities such as a fitness club, where the number of people who adopt walking, swimming, and the like as an exercise routine is increasing. Also, it is said that a considerable effect on prophylaxis or amelioration of a lifestyle-related disease might be attained through, in addition to exercise guidance, nutritional management in cooperation with a national registered dietitian.
A lifestyle-related disease is defined as “a group of diseases whose development and progress are associated with lifestyle such as an eating habit, an exercise habit, respite, smoking, and alcohol consumption”, and representative diseases include dental caries, periodontal disease, osteoporosis, alcoholic liver disease, obesity, gout (hyperuricemia), hypertension, diabetes mellitus, hyperlipidemia, heart disease, cerebral apoplexy, and cancer. “Arteriosclerosis” is known as a pathological condition associated with a lifestyle-related disease.
It is postulated that persistent high postprandial glucose levels induce an oxidative stress along with increased glycated protein and activated protein kinase C, and the oxidative stress thus induced causes vascular disorder.
The oxidative stress is considered to cause activation of blood vessel-constituting cells and blood cells such as monocytes and platelets and increase secretion of inflammatory cytokines and oxidized LDL (MDA-LDL), resulting in progression and aggravation of vascular disorder. Due to inflammation developed in the above process, the level of CRP, which is an inflammatory marker, also increases. It is considered that the above-described series of reactions lead to development and progression of arteriosclerosis (Non-Patent Document 3).
Homocysteine is an amino acid present in the blood. Homocysteine has become a focus of attention in recent years for its association with arteriosclerosis. It is considered that, in atherosclerosis, monocytes adhere to and infiltrate arterial endothelial cells in response to chemotactic factors secreted due to an endothelial cell injury, and monocytes differentiate into macrophages in intimae. Then, while they take up cholesterol in the blood to cause intimal hyperplasia, they break down to develop an atheromatous condition. It is considered that when homocysteine is accumulated in the blood, it causes autoxidation, and a substance such as radical oxygen produced during the oxidation process damages endothelial cells, increasing the likelihood of arteriosclerosis development (Non-Patent Document 4). Arteriosclerosis is also known as a complication of diabetes mellitus, and it is considered that arteriosclerosis and diabetes mellitus are closely associated.    Non-Patent Document 1: Prophylaxis of lifestyle-related disease and exercise and nutritional management, ISHII, Keiko et al., the Japanese Journal of Clinical Nutrition, Vol. 108, No. 2, February 2006    Non-Patent Document 2: Psychosomatic medical approach to lifestyle-related disease, YAMANAKA, Takao et al., Japanese Society of Psychosomatic Medicine, Vol. 46, No. 4, April 2006    Non-Patent Document 3: Journal of Clinical and Experimental Medicine, Vol. 218, No. 1, July 1st, 2006, YAMAGISHI, Shoichi    Non-Patent Document 4: Journal of Clinical and Experimental Medicine, 202(10): 789-793, 2002